Who is "we"? I think this had always been the wet dream of corporate types, not the users. In the PC space there are too many existing ecosystems to implement that kind of control (through Microsoft certainly tried with the whole "trusted computing" stuff) but as soon as there was an opportunity for a popular new "blue ocean" platform, they jumped.
You could see this most blatancy with ARM tablets. Microsoft released two versions of Windows, one for x86, one for ARM. The x86 one allowed installation of regular programs, the ARM version was restricted to Store apps. Made no sense from a technical perspective, the only reason is that they could.